Improvement in blackboard-rubbers



D. JAG-KSO N.

Buck-Board Rubber. N0.164,l73 Patentedl'une8,1875.

Fig- I Witnessesf Inventor.

NITED STATES PATENT OFFICE.

DAVID JACKSON, OF CHICAGO, ILL, ASSIGNOR TO ALFRED H. ANDREWS, HERBERT L. ANDREWS, AND THOMAS S. HAYDEN, OF SAME PLACE.

IMPROVEMENT IN BLACKBOARD-RUBBERS.

Specification forming part of Letters Patent No. 164,173, dated June 8, 1875 application filed March 9, 1875.

To all whom it may concern Be it known that I, DAVID JACKSON, of the city of Chicago, in the county of Cook and State of Illinois, have invented a new and useful Improvement in Blackboard-Rubbers or Erasers, of which the following is a full description, reference being had to the accompanying drawings, in which- Figure l is a side elevation Fig. 2 an end View.

This invention relates to that class of blackboard-erasers which have a continuous piece of carpet, or other material, so secured to a block that the carpet can be turned upon the block, when partly worn, presenting for use anew surfaoe; and it consists in providing a block, which receives the carpeting with a recess, and connecting to said block a handle adapted to enter said recess, and force the carpeting down therein, tightening the same and holding itin place.

In the drawings, A represents the main block; B, the handle; 0, the metal strips, by means of which A and B are connected together; D, the carpeting, or other material used for erasing. The upper portion of the block A is recessed, as shown at c. The lower part I) of the handle B has a shape similar to that of the recess 0. The two parts A B are secured together by means of metal pieces 0, which, for durability may be made of steel, as shown. C is connected to A at two points, a a, and to B at a single point, d, by means of headed pins, screws,or in other suitable manner, and so that the handle B is pivoted to the the part C. The erasing material D is a continuous strip of material into which the block A is to be inserted before the parts C are secured thereto. Then the parts C are to be secured both to A and B, as described, the part B being in the position represented by the dotted lines in Fig. 2. Then, by turning the handle B, and bringing it into the position represented in Fig. 2, the loose material will be forced down into the recess 0 by the lower part of the handle, and the several parts will be firmly secured in place. The dotted lines in the lower part of Fig. 2, indicate the position of the erasing material when it is first applied to A, and before the handle B has been brought to its place. 7

After the surface of the erasing material on the face of A has been worn by loosening the handle, and bringing it again into the position shown by the dotted lines in Fig. 2, D can be turned upon A, so as to present a new erasing-surface. When the entire surface of the erasing material D has become worn so as to be unfit for use, one of the connectingpieces C can be easily removed, and the worn erasing materialD be replaced by a new piece. The distance between A and B depends upon the thickness of the erasing material used. The part b of the handle B might be made slightly eccentric, but I do not deem this necessary.

I do not claim, broadly, an eraser having a continuous strip of erasing material provided with an interior support, and combined with a handle; but

What I do claim as new, and desire to secure by Letters Patent, is as follows:

A blackboard rubber, consisting of the parts A, B, C, and D, constructed and arranged to operate substantially as and for the purposes specified.

DAVID JACKSON. Witnesses:

E. A. WEsT, 0. W. Bonn. 

